Automatic darkening filter (ADF) eye protection devices are employed in a number of fields. One such field is welding where ADF technology provides protection for welders' eyes from the intense light levels generated in the welding process. Eye protection devices may also be used in other areas where bright light may be generated such as from lasers, explosives, etc.
ADF systems often include a liquid crystal device (LCD) that is generally driven with shade voltages applied across the filter corresponding to an alternating current (AC) square wave, To provide this square wave voltage, the voltage polarity across the filter is constantly being reversed. According to current technology, when the polarity of the voltage across the filter is switched from positive to negative or negative to positive, it is switched very close to instantaneously. Such near instantaneous switching causes high peak currents that stress electronic components and produce high battery drain.
In view of these known disadvantages, it would be advantageous to provide a mechanism for ADF circuitry that eliminates, or at least significantly reduces, the previously experienced high battery drain and component stress.